冬小麦叶片形状系数的变异性

摘要

研究了2014-10-2015-06生长季内6个不同熟性冬小麦品种全生育期内叶片形状系数的变化规律,将小麦生育期划分为出苗、返青、拔节、抽穗、开花、成熟等6个不同生长阶段,依次采样计算各个阶段的α均值,同时考虑α值在单个植株不同叶片之间的差异,以及不同冬小麦品种之间的差异.结果表明:α值总体在0.59到0.71之间,随冬小麦生育期的变化而变化,自苗期到开花期波动增大,开花后缓慢下降;在单个植株之内,α值变异性较大,开花期最为稳定,开花后变异性增加;不同熟性冬小麦品种之间,α值在拔节、抽穗和开花期表现出显著差异,而在出苗、返青和成熟期,差异不显著.因此,建议最好在不同的作物生长阶段采用不同的叶片性状系数,以提高叶面积模拟和预测精度.对全生育期3种熟性6个冬小麦品种的1 485个叶片的面积和长宽乘积进行线性回归分析,可知总体的冬小麦叶片形状系数值约为0.66.以叶面积模型IA=0.66×L×W来估算冬小麦叶片面积,其总体的相对均方根误差(RRMSE)约为4.40％,绝对相对误差(absolute relative error,ARE)约为13.05％,在5种不同叶面积估算模型中精度最高,因此推荐该模型用于估算田间小麦叶片面积.%In this study,the temporal and spatial variations of α values of winter wheat had been investigated through a field experiment conducted from October 2014 to June 2015.A total of six wheat cultivars (varieties) (two early ripening,two medium ripening,and two late ripening) were involved.The whole growth season of wheat was divided into six different stages,i.e.emergence,greening,jointing,heading,flowering and maturity.Wheat plants were randomly collected and all leaves were cut off and measured for their length,width,and area with a digital leaf area scanner.Then,α values were calculated for each leaf.The variations of α values were analyzed for different growth stages,among different wheat cultivars,and among different leaves of a single plant.The results showed that α value ranged from 0.59 to 0.71 and varied at different growth stages.It increased with fluctuations from emergence to flowering stage,and then decreased.The uncertainties of α values,measured by standard deviation and coefficient of variation,decreased first and then increased slightly.Within a single plant,α values varied at different stages but remained relatively stable at flowering stage.The uncertainty of α value increased after flowering.Among different wheat cultivars of various ripening traits,α values were significantly different at jointing,heading and flowering stages,but not significantly different at emergence,greening and maturity stages.Thus,it is better to adopt various α values at different growth stages so as to improve the accuracy of simulation and prediction of leaf area of winter wheat.Based on linear regression analysis of leaf area and product of leaf length and width of 1 485 leaf samples of six different wheat cultivars,the general value of α was about 0.66.Then,when simulating wheat leaf areas with the model of LA =0.66 × L × W,the relative root mean square error (RRMSE) and absolute relative error (ARE) were 4.40％ and 13.05％,respectively.The accuracy was the highest among the five different models investigated for estimation of wheat leaf area.Thus,this model was recommended for the estimation of wheat leaf area and leaf area index in future field studies.